There are hundreds of indications leading us to conclude that at every moment there is in us an infinity of perceptions, unaccompanied by awareness or reflection; that is, of alterations in the soul itself, of which we are unaware because the impressions are either too minute or too numerous, or else too unvarying, so that they are not sufficiently distinctive on their own. But when they are combined with others they do nevertheless have their effect and make themselves felt, at (...) least confusedly, within the whole. (Leibniz, 1704/1981, p. 53). (shrink)
Whenever knowledge of the possible interpretation or conceptualization of some- thing helps in perceiving that thing, we say the processing is conceptually driven. That is, the process starts with conceptualization of what might be present and then looks for confirming evidence, biasing the processing mechanisms to give the expected result... Conceptually driven processing and data-driven processing almost always occur together, with each direction of processing contributing something to the total analysis. (Lindsay and Norman 1977, p. 13).
Salience of Peripheral 2 Abstract The three experiments reported document a slowing of peripheral target acquisition associated with the presence of a gaze-contingent window. This window effect was shown for displays using either moving video or still images. The window effect was similar across a resolutiondefined window condition and a luminance-defined window condition suggesting that peripheral image degradation is not a prerequisite of this effect. The window effect was also unaffected by the type of window boundary used (sharp or blended). (...) These results are interpreted in terms of an attentional bias resulting in a reduced saliency of peripheral targets due to increased competition from items within the window. We discuss the implications of the window effect for investigating the perceptual processes involved in natural scenes and for gaze-contingent multiresolutional displays (GCMRDs) that have been proposed to solve the processing and bandwidth bottleneck in many single-user displays, by dynamically placing high-resolution in a window at the center of gaze, with lower resolution everywhere else. (shrink)
In three experiments, participants' visual span was measured in a comparative visual search task in which they had to detect a local match or mismatch between two displays presented side by side. Experiment 1 manipulated the dif®culty of the comparative visual search task by contrasting a mismatch detection task with a substantially more dif®cult match detection task. In Experiment 2, participants were tested in a single-task condition involving only the visual task and a dual-task condition in which they concurrently performed (...) an auditory task. Finally, in Experiment 3, participants performed two dual-task conditions, which differed in the dif®culty of the concurrent auditory task. Both the comparative search task dif®culty (Experiment 1) and the divided attention manipulation (Experiments 2 and 3) produced strong effects on visual span size. q 2001 Elsevier Science B.V. All rights reserved. (shrink)
In 5 experiments, participants read text that was briefly replaced by a transient image for 33 ms at random intervals. A decrease in saccadic frequency, referred to as saccadic inhibition, occurred as early as 60 –70 ms following the onset of abrupt changes in visual input. It was demonstrated that the saccadic inhibition was influenced by the saliency of the visual event (Experiment 3) and was not produced in response to abrupt but irrelevant auditory stimuli (Experiment 1). Display changes restricted (...) to an area either inside or outside the perceptual span required for normal reading produced strong saccadic inhibition (Experiment 2). Finally, Experiments 4 and 5 demonstrated higher level cognitive or attentional modulation of the saccadic inhibition effect. (shrink)
& The present study investigated saccadic inhibition in both voluntary and stimulus-elicited saccades. Two experiments examined saccadic inhibition caused by an irrelevant flash occurring subsequent to target onset. In each trial, participants were required to perform a single saccade following the presentation of a black target on a gray background, 48 to the left or to the right of screen center. In some trials (flash trials), after a variable delay, a 33-msec flash was displayed at the top and bottom third (...) of the monitor (these regions turned white). In all experimental conditions, histograms of flash-to-saccade latencies documented a decrease in saccadic frequency, forming a dip, time-locked to the flash and occurring as early as 60–70 msec following its onset. The fast latency of this effect strongly suggests a low-level, reflex-like, oculomotor effect, which was referred to as saccadic inhibition. A novel procedure was developed to allow comparisons of saccadic inhibition even across conditions, which in the absence of a flash (no-. (shrink)
In a recent paper, Graf and Komatsu (1994) argued that the process dissociation procedure (Jacoby, 1991) is limited in its ability to separate and measure conscious and unconscious forms of memory and so should be "handIed with caution". Given that the study of unconscious influences has always posed a difficult problem for memory researchers, we agree with the general emphasis on caution. In this paper, we too advocate caution, especially as it applies to the use of indirect tests, assessing Graf (...) and Komatsu’s critique, and using the process dissociation procedure. We address the substantive issues raised by Graf and Komatsu and also point out the errors, both factual and logical, in their paper. Any method proposing to provide separate measures of conscious and unconscious influences requires judicious use and a careful examination of its underlying assumptions. The assumptions underlying the process dissociation framework are supported by a large number of experiments spanning a diverse range of.. (shrink)
A critical prediction of the E-Z Reader model is that experimental manipulations that disrupt early encoding of visual and orthographic features of the fixated word without affecting subsequent lexical processing should influence the processing difficulty of the fixated word without affecting the processing of the next word. We tested this prediction by monitoring participants’ eye movements while they read sentences in which a target word was presented either normally or altered. In the critical condition, the contrast between the target word (...) and the background was substantially reduced. Such a reduction in stimulus quality is typically assumed to have an impact that is largely confined to a very early stage of word recognition. Results were consistent with the E-Z Reader model: This faint presentation had a robust influence on the duration of fixations on the target word without substantially altering the processing of the next word. (shrink)
Several gaze contingent studies that used a fixed delay between physical eye movements and a display change documented a dip in the fixation duration distributions (e.g., Blanchard et al. 1984; McConkie et al. 1985; van Diepen et al. 1995). In a study by van Diepen et al. (1995), a moving mask paradigm was employed in which subjects searched line drawings of everyday scenes for non-objects. The appearance of the mask was delayed relative to the end of a saccade (beginning of (...) fixation) by 17, 46, 76 or 121 msec. All fixation duration distributions in the masking conditions exhibited a dip with longer masking delays resulting in the dip occurring at longer fixation durations. In contrast, a no-mask condition did not produce a dip. Similar effects in reading were reported by Blanchard et al. (1984), and McConkie et al. (1985). In both these studies the text was.. (shrink)
Reingold and MerikleÕs (1988, 1990) critique of the classic dissociation paradigm identiﬁed several issues as inherent problems that severely undermine the utility of this paradigm. Erdelyi (2004) extending his prior analysis (Erdelyi, 1985, 1986) points out several additional factors that may complicate the interpretation of empirically obtained dissociations. The goal of the present manuscript is to further discuss some of these commonly neglected interpretive diﬃculties. Ó 2003 Elsevier Inc. All rights reserved.
It is argued here that a critical prediction of the E-Z Reader model is that experimental manipulations that disrupt early encoding of visual and orthographic features of the fixated word without affecting subsequent lexical processing should influence the processing difficulty of the fixated word without producing any processing effect on the next word. This prediction is explained and illustrated.